Evidence supporting the role of telomerase, MMP-9, and SIRT1 in attention-deficit/hyperactivity disorder (ADHD).

Growing evidence suggests that telomeres, telomerase, matrix metalloproteinase-9 (MMP-9), and SIRT1 (sirtuin1) are involved in the pathophysiology of neuropsychiatric and neurodevelopmental disorders. However, whether these molecules are contributors to attention-deficit/hyperactivity disorder (ADHD) has been little explored and poorly understood. This study aimed to determine the potential role of telomerase, MMP-9, and SIRT1 in children with ADHD. The study was performed on 46 children with ADHD aged between 8 and 14 and 43 healthy children matching in age and gender. Children were evaluated by Kiddie-Sads-Present and Lifetime Version, Conners' Parent Rating Scale-Revised Short Form (CPRS-RS) and Stroop test. Serum telomerase, MMP-9, and SIRT1 levels were measured by a quantitative sandwich enzyme-linked immunosorbent assay. MMP-9 and telomerase levels were significantly higher and SIRT1 levels were significantly lower in patients with ADHD than those of controls. All three molecules were significantly associated with both the severity of ADHD symptoms and cognitive functions. This is the first attempt to indicate that the important role of telomerase, MMP-9, and SIRT1 in ADHD, and the association of all these molecules with the severity of ADHD and cognitive functions, but future studies are required to verify these results.

Evaluation of the associations between endothelial dysfunction, inflammation and coagulation in Crimean-Congo hemorrhagic fever patients.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne zoonotic viral disease. The aim of this study was to evaluate the association between inflammation, coagulation and endothelial dysfunction in CCHF. The study population consisted of 40 patients and 50 healthy controls. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), endocan, high sensitive C-reactive protein (hsCRP), international normalized ratio (INR), prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelets values were determined in blood samples. Median hsCRP (p < 0.0001), ALT (p < 0.001), AST (p < 0.001) and aPTT (p < 0.001) values were found to be higher in CCHF patients than in the healthy control subjects. In contrast, median endocan (p = 0.0006) and platelet (p < 0.001) concentrations were found to be lower in CCHF patients than in healthy controls. Serum hsCRP concentrations positively correlated with PT, aPTT and INR in CCHF patients, whereas serum endocan levels were not correlated with hsCRP, PT, aPTT and INR. In conclusion, endothelial dysfunction is one of the key steps in CCHF disease development and serum endocan may be used as a biomarker to evaluate endothelial dysfunction in patients. There is no relationship between increased inflammation and endothelial dysfunction. Coagulation abnormalities might be related to the impaired hepatic synthetic function of coagulation factors. Increased hsCRP concentrations may have a compensatory role in restoring impaired hemostasis in CCHF. Further research is needed to confirm these findings and to examine possible explanations.

The Association of Plasminogen Activator Inhibitor Type 1 (PAI-1) Level and PAI-1 4G/5G Gene Polymorphism with the Formation and the Grade of Endometrial Cancer.

Plasminogen activator inhibitor type 1 (PAI-1) is a serine protease inhibitor (Serpine 1), and it inhibits both tissue plasminogen activator and urokinase plasminogen activator which are important in fibrinolysis. We aimed to find whether there is a possible association between PAI-1 level, PAI-1 4G/5G polymorphism, and endometrial cancer. PAI-1 levels in peripheral blood were determined in 82 patients with endometrial carcinoma and 76 female healthy controls using an enzyme-linked immunoassay (ELISA). Then, the genomic DNA was extracted and screened by reverse hybridization procedure (Strip assay) to detect PAI 1 4G/5G polymorphism. The levels of PAI-1 in the patients were higher statistically in comparison to controls (P < 0.001). The distribution of PAI-1 4G/5G polymorphism was quite different between patients and controls (P = 0.008), and 4G allelic frequency was significantly higher in the patients of endometrial cancer than in controls (P = 0.026). We found significant difference between Grade 1 and Grade 2+3 patients in terms of the PAI-1 levels (P = 0.047). There was no association between PAI-1 4G/5G polymorphism and the grades of endometrial cancer (P = 0.993). Our data suggest that the level of PAI-1 and PAI-1 4G/5G gene polymorphism are effective in the formation of endometrial cancer. PAI-1 levels are also associated with the grades of endometrial cancer.

Relationship of plasma cell-free DNA level with mortality and prognosis in patients with Crimean-Congo hemorrhagic fever.

Crimean-Congo hemorrhagic fever (CCHF) is a viral infection. Circulating plasma cell-free DNA (pcf-DNA) is a novel marker indicating cellular damage. So far, the role of pcf-DNA did not investigate in CCHF patients. In the current study, pcf-DNA levels were investigated in CCHF patients with different clinical severity grades to explore the relationship between circulating pcf-DNA level, virus load, and disease severity. Seventy-two patients were categorized as mild, intermediate, and severe based on severity grading scores. The pcf-DNA level was obtained from all participants on admission and from the survivors on the day of the discharge. The controls consisted of 31 healthy. Although the pcf-DNA level at admission was higher in patients than in the controls, the difference was not statistically significant (P = 0.291). However, at admission and in the convalescent period, the difference between pcf-DNA levels in mild, intermediate, and severe patient groups was significant. The pcf-DNA level in severe patients was higher than in the others. Furthermore, compared to survivors, non-survivors had higher pcf-DNA levels at admission (P = 0.001). A direct relationship was found between the pcf-DNA level and the viral load on the day of discharge in surviving patients. ROC curve analysis identified a pcf-DNA level of 0.42 as the optimal cut-off for prediction of mortality. The positive predictive value, negative predictive value, specificity, and sensitivity for predicting mortality was 100%, 72%, 100%, and 79%, respectively. In summary, our findings revealed that pcf-DNA levels may be used as a biomarker in predicting CHHF prognosis.

Decreased Chitotriosidase Activity and Levels in Familial Mediterranean Fever.

Different studies have demonstrated changes in chitotriosidase (ChT) activity and concentrations in multiple diseases. However, changes in ChT activity and concentrations have not been concurrently evaluated in patients with Familial Mediterranean Fever (FMF). In this study, we analyzed the changes in serum ChT activity and concentrations in patients with FMF. The study included a total of 80 patients with FMF and 80 healthy controls. ChT enzyme activity and concentrations were measured and then compared between the groups. ChT activity was measured by using fluorometric ELISA and ChT concentrations were measured by using colorimetric ELISA methods. The median ChT activity was 10.00 (6.00-15.00) nmol/mL/hr in the patients and 14.00 (6.25-20.75) nmol/mL/hr in the controls. There was a statistically significant difference in the ChT activity between the controls and patients (P = 0.027). The median ChT concentrations were 65.40 (46.20-84.92) pg/mL and 125.00 (75.72-143.95) pg/mL in the patients and controls, respectively (P < 0.001), which were expressed as median percentiles (25th-75th). Additionally, we found no correlation between C-reactive protein and ChT activity (P = 0.978, r = 0.003) and concentrations (P = 0.446, r = -0.87). Serum ChT enzyme activity and concentrations may not be considered as a biomarker in FMF patients taking colchicine. New studies are needed to evaluate the changes of enzyme activity and concentration in colchicine-negative patients.

Evaluation of the relationship between serum levels of VEGF and sVEGFR1 with mortality and prognosis in patients with Crimean-Congo hemorrhagic fever.

The most accepted view to explaining the pathogenesis of Crimean-Congo hemorrhagic fever (CCHF) is endothelial damage. This study was conducted in a University hospital to investigate the serum levels and prognostic significance of the vascular endothelial growth factor (VEGF) and its receptor, soluble fms-like tyrosine kinase-1 receptor (sVEGFR-1) in CCHF. Forty-eight consecutive hospitalized CCHF patients (grouped into severe illness and non-severe illness) and 40 healthy adults, as controls were enrolled. There was statistically significant difference for each of VEGF (P = 0.003), and sVEGFR1 (P = 0.0001) between the patients and controls. VEGF and sVEGFR1 levels in patients with severe CCHF were found to be higher than in the control group (P = 0.0001 and P = 0.0001, respectively). A significant difference was found in VEGF (P = 0.003) and sVEGFR1 (P = 0.0001) levels when compared to patients with CCHF who died and who recovered. In patients in the group with severe illness, the sensitivity, specificity, and the area underneath the ROC curve (AUROC) belonging to those cut-off points of VEGF and sVEGFR1 were 66.7%, 76.2%, 0.747, and 77.8%, 81%, 0.849, respectively. In non-survivors, the sensitivity, specificity, and the AUROC belonging to those cut-off points of VEGF and sVEGFR1 defined as 77.8%, 76.9%, 0.813, and 88.9%, 97.4%, 0.912, respectively. In conclusion, high sensitivity, specificity, and the AUROC values were found in sVEGFR1 levels especially in the severely ill and non-survivors. Therefore, sVEGFR1 may be an important biomarker for determining the risk of severity and death as result of infection with CCHF virus.

Effects of electromagnetic radiation from 3G mobile phone on heart rate, blood pressure and ECG parameters in rats.

Effects of electromagnetic energy radiated from mobile phones (MPs) on heart is one of the research interests. The current study was designed to investigate the effects of electromagnetic radiation (EMR) from third-generation (3G) MP on the heart rate (HR), blood pressure (BP) and ECG parameters and also to investigate whether exogenous melatonin can exert any protective effect on these parameters. In this study 36 rats were randomized and evenly categorized into 4 groups: group 1 (3G-EMR exposed); group 2 (3G-EMR exposed + melatonin); group 3 (control) and group 4 (control + melatonin). The rats in groups 1 and 2 were exposed to 3G-specific MP's EMR for 20 days (40 min/day; 20 min active (speech position) and 20 min passive (listening position)). Group 2 was also administered with melatonin for 20 days (5 mg/kg daily during the experimental period). ECG signals were recorded from cannulated carotid artery both before and after the experiment, and BP and HR were calculated on 1st, 3rd and 5th min of recordings. ECG signals were processed and statistically evaluated. In our experience, the obtained results did not show significant differences in the BP, HR and ECG parameters among the groups both before and after the experiment. Melatonin, also, did not exhibit any additional effects, neither beneficial nor hazardous, on the heart hemodynamics of rats. Therefore, the strategy (noncontact) of using a 3G MP could be the reason for ineffectiveness; and use of 3G MP, in this perspective, seems to be safer compared to the ones used in close contact with the head. However, further study is needed for standardization of such an assumption.

The impact of Dicer, Drosha, and Exportin-5 levels in polycystic ovary syndrome (PCOS) diagnosis and phenotyping.

INTRODUCTION: Polycystic ovary syndrome (PCOS) is a very common heterogeneous endocrine and gynaecological disease in reproductive women. Early identification and treatment of patients are necessary to prevent future cardiometabolic and reproductive complications. In our study, we aimed to investigate whether Drosha, Exportin-5 (XPO5), and Dicer, which are involved in miRNA formation, are useful markers in the diagnosis of the disease. MATERIAL AND METHODS: Patients who presented to our clinic with complaints such as menstrual irregularity, hirsutism, and acne were diagnosed with polycystic ovary after excluding other possible diagnoses, and if they meet two-thirds of the Rotterdam diagnostic criteria, they were included in the study. Thirty patients with polycystic ovaries and 35 healthy controls were included in this study. RESULTS: The mean values of XPO5, Drosha, and Dicer markers were significantly higher in the PCOS group when compared with the control group. With an XPO5 value > 1.70, we found the PCOS with 94% probability, 86.7% sensitivity, and 91.4% specificity. Moreover, if the Drosha value was > 0.166, it was expected that the patient would be diagnosed as PCOS with a probability of 75%, with 66.7% sensitivity and 71.4% specificity. A statistically significant cut-off value could not be obtained for Dicer. CONCLUSIONS: In our study, the levels of all three markers were found to be significantly higher in the PCOS group compared to the control group. It suggests that they can be used in the early diagnosis of PCOS patients without full-blown disease. However, this preliminary study should be supported by larger-scale studies.

SIRT1, MMP-9 and TIMP-1 levels in children with specific learning disorder.

BACKGROUND: Specific Learning Disorder (SLD) is a common developmental and neurobiological disorder of childhood characterized by impairment of functionality in one or more areas such as reading, writing, mathematics, listening, speaking, and reasoning. The etiology of SLD is still not fully understood. The aim of this study was to evaluate children with SLD to investigate the potential role of MMP-9, TIMP-1 and SIRT-1, which have important roles in synaptic plasticity, cognitive functions, learning and memory, and are known to be associated with various psychiatric disorders. METHODS: The study was conducted with 44 outpatients aged 8-14 years who were diagnosed with SLD according to DSM-5 in the outpatient clinic and a control group of 44 age, gender and education level-matched healthy children. The groups were compared in respect of serum levels of MMP-9, TIMP-1 and SIRT-1, evaluated using the ELISA method. RESULTS: Serum MMP-9 levels were significantly lower in children in the SLD group than in the control group, while TIMP-1 was higher. No difference was determined between the groups in respect of the SIRT1 levels. SLD severity was negatively correlated with MMP-9 levels and positively correlated with TIMP-1 levels. CONCLUSIONS: MMP-9 appear to contribute to hippocampal-dependent memory and learning by modulating long-term synaptic plasticity. The findings of this study also reinforce the idea that deregulation of the MMP-9/TIMP-1 ratio may impact learning and play a role in SLD. These findings will help to elucidate the etiology of SLD. Furthermore, understanding molecular pathways can contribute to the discovery of certain biomarkers in SLD pathogenesis and the development of new treatment possibilities.

Serum Vascular Endothelial Growth Factor and Vascular Endothelial Growth Factor Receptor-1 Levels in Patients With Fibromyalgia Syndrome.

OBJECTIVES: This study aims to compare the serum vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-1 (VEGFR-1) levels between patients with fibromyalgia syndrome (FMS) and healthy controls. PATIENTS AND METHODS: The study included 40 female patients (mean age 39.9±10.2 years; range, 22 to 52 years) diagnosed with primary FMS according to the American College of Rheumatology criteria (1990) and 40 healthy female volunteers (mean age 40.9±8.3 years; range, 25 to 53 years). The sociodemographic data of both groups were recorded. The disease duration and the number of tender points were recorded for patients with FMS, and venous blood samples were collected from the two groups for the measurement of serum VEGF and VEGFR-1 levels. RESULTS: The FMS and control groups were comparable in terms of age and body mass index (p>0.05). A comparison of the serum VEGF levels of the FMS and control groups revealed a statistically insignificant difference (p>0.05), while a comparison of the serum VEGF-1 levels of the FMS and control groups revealed a statistically significant difference (p<0.05). CONCLUSION: Serum VEGFR-1 levels were higher in patients with FMS, while the serum VEGF levels of the FMS patients did not differ from those of the healthy controls.

Thiol Disulfide Homeostasis in Schizophrenic Patients Using Atypical Antipsychotic Drugs.

OBJECTIVE: Schizophrenia is a severe, debilitating mental disorder characterized by behavioral abnormalities. Although several studies have investigated the role of oxidative stress and the effects of antipsychotic drugs on oxidative markers in schizophrenia, adequate information is not available on these issues. The aim of this study is to determine the changes in oxidative status and thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs. METHODS: Thirteen schizophrenic patients using atypical antipsychotic drugs and 30 healthy controls were included this study. The concentrations of total oxidant status (TOS), total antioxidant status (TAS), native thiol, total thiol, and disulfide levels were determined in the study population. RESULTS: The TAS (p=0.001), total thiol, and native thiol levels (p＜0.001) were higher in the patients compared to the controls, whereas the TOS and disulfide levels were lower in the patients than in the controls (p＜0.001). CONCLUSION: These results may suggest that atypical antipsychotic drugs have a useful therapeutic effect by reducing oxidative stress via the inhibition of the formation of disulfide bonds. The study population number was one of the limitations of this study. Therefore, further studies are needed to establish the association between thiol disulfide homeostasis in schizophrenic patients using atypical antipsychotic drugs.

Increased Irisin Concentrations in Patients with Crimean- Congo Hemorrhagic Fever.

Crimean-Congo Hemorrhagic Fever (CCHF) is a life-threatening viral infection. The pathogenesis of the disease is not well understood. The aim of this study was to determine the change in irisin concentrations in patients with CCHF. The study included a total of 30 patients with CCHF and 30 control participants. Irisin concentrations were determined using a commercial ELISA kit. Median irisin concentrations were 9.03 (5.81-12.22) µg/mL and 4.2 (3.39-7.62) µg/mL, respectively, in each group. There was no correlation between irisin and disease severity. Any correlations between irisin, and lactate dehydrogenase (LDH), international normalization ratio (INR), Alanine aminotransferase (ALT), aspartate aminotransferase (AST), platelets, activated partial thromboplastin time (aPTT), D-dimer and hemoglobin, were also investigated. There were statistically significant positive correlations between the values of irisin, and platelet (p = 0.005, r: 0.369), ALT (p = 0.049, r: 0.261), INR (p = 0.006, r: 0.359) and aPTT values (p = 0.002, r: 0.405). A negative correlation was also found between the values of irisin and LDH (p = 0.008, r: －0.348). No correlations were determined between the values of irisin, and AST, hemoglobin and D-dimer. These results suggest that irisin may have a role in CCHF.

Examination of free radical metabolism and antioxidant defence system elements in patients with obsessive-compulsive disorder.

Free radicals and oxidative stress are involved in the pathogenesis of various diseases. Malondialdehyde (MDA) is a natural product of lipid peroxidation in all mammalian cells. Vitamins C and E are nonenzymatic antioxidant structures. Our study investigated the role of free radicals in the obsessive-compulsive disorder (OCD). The participants were 30 patients with OCD that were drug-free at least for a month and a control group of 30 healthy subjects, matched with respect to age and sex. In both groups, the levels of erythrocyte malondialdehyde and the plasma vitamin C and E concentrations were measured. The levels of malondialdehyde were significantly higher in the patient group than in the control group (p<.01). The levels of plasma vitamin E were significantly lower in the patient than in the control group (p<.02). Although our patient group had slightly lower concentrations of plasma vitamin C compared to our control group, the difference between these two groups was not statistically significant. There was a significant correlation between increasing malondialdehyde levels and decreasing vitamin E concentrations. This study shows the presence of a significant relationship of OCD and oxidative stress, and consequently, an involvement of free radicals and of the antioxidant defence. Biochemical studies may contribute to the understanding of OCD and its treatment.

Intraerythrocyte antioxidant enzyme activities in migraine and tension-type headaches.

BACKGROUND: The pathophysiology of migraine and other headaches is still unknown, and research is mostly done on neurotransmitter, biochemical and vascular mechanisms. The aim of this study was to examine the role of antioxidant enzymes in the pathophysiology of headache in the interictal period of the pain process. METHODS: In this study, glutathione peroxidase, catalase and superoxide dismutase enzyme activities were investigated in 88 cases, which included 11 migraine cases with aura, 17 migraine without aura, 32 chronic type tension headache and 28 control cases. RESULTS: In migraine cases, superoxide dismutase and glutathione peroxidase enzyme activities were statistically lower than in the tension headache and control groups. The differences between tension-type headache and control groups were found statistically insignificant. CONCLUSIONS: Low intraerythrocytes, superoxide dismutase and glutathione peroxidase levels may play an important role in the etiology of migraine.

Some acute phase reactants and cholesterol levels in serum of patient with Crimean-Congo haemorrhagic fever.

The purpose of this study is to determine erythrocyte sedimentation rate (ESR), C - reactive protein (CRP), serum amyloid-A (SAA) and cholesterol levels in patients with Crimean-Congo Hemorrhagic Fever (CCHF) and determine the relationship of these parameters with the severity of disease. By polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) method 40 patients were diagnosed as CCHF and 39 volunteer without any systemic disease whose blood were taken and their serum separated. SAA, CRP and ESR were measured with ELISA, nephelometry and Mix-Rate x100 vital diagnostic device, respectively, in serum samples. High density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol levels were determined by using autoanalyzer HDL, LDL and total cholesterol kit (Syncron LX20). Statistically significant difference was determined between patients and controls in terms of the levels of SAA, CRP, HDL, LDL and total cholesterol (p<0.05). However, there was no significant difference between the groups in terms of the levels of ESR. In addition, neither SAA, CRP, ESR nor HDL, LDL and total cholesterol levels varied with the severity of disease in the cases assessed (p>0.05). Using of CRP and SAA together might increase the sensitivity of diagnosis of CCHF infection. However, none of the parameters investigated in this study were found to be a proper marker of the prognosis in CCHF. Cholesterol levels were significantly decreased in patients with CCHF, which was suggested to be associated with the increased serum levels of SAA in the patient group.

Comparison of oxidant/antioxidant, detoxification systems in various tissue homogenates and mitochondria of rats with diabetes induced by streptozocin.

OBJECTIVE: Oxidative stress is considered to be the main factor in the development of diabetic complications and tissue injury. our objective was to investigate and compare the oxidant/antioxidant conditions and detoxification mechanisms of the liver, lung, kidney, cardiac tissues, and mitochondria of rats with diabetes induced by streptozocin (STZ). METHODS: Rats with diabetes induced by streptozocin were anesthetized by administering 90 mg/kg ketamine hydrochloride and 3 mg/kg xylazine hydrochloride. Thoracic cavities were incised open; liver, lung, kidney, and cardiac tissues were removed and stored at -70°C. All samples were homogenized and mitochondrial fractions were separated. Total Antioxidant Status (TAS), Total Oxidant Status (TOS), Oxidative Stress Index (OSI), Paraoxonase (PON), Arylesterase, Catalase (Cat), Malondialdehyde (MDA), and Glutathion-S-transferase were measured in each fraction. RESULTS: MDA and TOS levels were significantly increased in liver tissues, and T OS and OSI were increased in the mitochondrial fractions of diabetic rats. These increases were not statistically significant compared to the control group. No significant differences were determined in the antioxidant and GST activities. CONCLUSION: According to our results, oxidative stress has not developed in rats with diabetes induced by streptozocin. The detoxification system was induced; however, this induction did not differ significantly from the controls.

Determination of serum adenosine deaminase and xanthine oxidase levels in patients with crimean-congo hemorrhagic fever.

OBJECTIVE: Crimean-Congo hemorrhagic fever is an acute viral hemorrhagic fever with a high mortality rate. Despite increasing knowledge about hemorrhagic fever viruses, little is known about the pathogenesis of Crimean-Congo hemorrhagic fever. In this study, we measured serum adenosine deaminase and xanthine oxidase levels in Crimean-Congo hemorrhagic fever patients. METHODS: Serum adenosine deaminase levels were measured with a sensitive colorimetric method described by Giusti and xanthine oxidase levels by the method of Worthington in 30 consecutive hospitalized patients (mean age 42.6 +/- 21.0). Laboratory tests confirmed their diagnoses of Crimean-Congo hemorrhagic fever. Thirty-five subjects (mean age 42.9 +/- 19.1) served as the control group. RESULTS: There was a significant difference in adenosine deaminase and xanthine oxidase levels between cases and controls (p<0.05). However, neither adenosine deaminase nor xanthine oxidase levels varied with the severity of disease in the cases assessed (p>0.05). CONCLUSION: Adenosine deaminase and xanthine oxidase levels were increased in patients with Crimean-Congo hemorrhagic fever. Elevated serum xanthine oxidase activity in patients with Crimean-Congo hemorrhagic fever may be associated with reactive oxygen species generated by the xanthine/xanthine oxidase system during inflammatory responses. In addition, elevated lipid peroxidation may contribute to cell damage and hemorrhage. The association of cell damage and hemorrhage with xanthine oxidase activity should be further investigated in large-scale studies.

Determination of serum adenosine deaminase and xanthine oxidase levels in patients with crimean-congo hemorrhagic fever

OBJECTIVE: Crimean-Congo hemorrhagic fever is an acute viral hemorrhagic fever with a high mortality rate. Despite increasing knowledge about hemorrhagic fever viruses, little is known about the pathogenesis of Crimean-Congo hemorrhagic fever. In this study, we measured serum adenosine deaminase and xanthine oxidase levels in Crimean-Congo hemorrhagic fever patients. METHODS: Serum adenosine deaminase levels were measured with a sensitive colorimetric method described by Giusti and xanthine oxidase levels by the method of Worthington in 30 consecutive hospitalized patients (mean age 42.6 ± 21.0). Laboratory tests confirmed their diagnoses of Crimean-Congo hemorrhagic fever. Thirty-five subjects (mean age 42.9 ± 19.1) served as the control group. RESULTS: There was a significant difference in adenosine deaminase and xanthine oxidase levels between cases and controls (p<0.05). However, neither adenosine deaminase nor xanthine oxidase levels varied with the severity of disease in the cases assessed (p>0.05). CONCLUSION: Adenosine deaminase and xanthine oxidase levels were increased in patients with Crimean-Congo hemorrhagic fever. Elevated serum xanthine oxidase activity in patients with Crimean-Congo hemorrhagic fever may be associated with reactive oxygen species generated by the xanthine/xanthine oxidase system during inflammatory responses. In addition, elevated lipid peroxidation may contribute to cell damage and hemorrhage. The association of cell damage and hemorrhage with xanthine oxidase activity should be further investigated in large-scale studies.